Standard ceiling lamp fixtures for use with fluorescent lamps are ordinarily modular in design and fit into standard ceiling modular fixtures. Many such fixtures are designed to accept 4-foot long fluorescent lamps, typically operating at 40 watts each. Fluorescent light fixtures most commonly employ tubular fluorescent lamps. Most common of these is the T-8 fluorescent lamp. The T-8 fluorescent lamp typically is available in several nominal lengths of 48 inches, 36 inches and 24 inches. There are numerous choices of fluorescent light fixtures. These modular ceiling fixtures are as short as the 4-foot lamps they are designed to accept.
Recently introduced into the American market place, the T-5 fluorescent lamp provides a more energy efficient fluorescent lamp than that of the T-8 fluorescent lamp. The T-5 fluorescent lamp is now being adopted by light fixture manufacturers. The T-5 fluorescent lamps have metric dimensions with nominal lengths of 1149 mm (45.24 in.), 849 mm (33.43 in.), and 549 mm (21.61 in.) all of which are substantially smaller than the nominal lengths of the T-8 fluorescent lamp. In addition, the T-5 lamps exhibit favorable energy efficiencies. These features and other desirable characteristics, make the T-5 fluorescent lamp an attractive option for light engineers who may consider retrofitting the conventional T-8 fluorescent fixtures. A retrofit would enable the use of the same conventional T-8 fluorescent fixture with the new T-5 fluorescent lamp. Since retrofitting the conventional T-8 fluorescent fixtures is a reasonable solution, cost conscious fixture manufacturers are continuing to produce the conventional T-8 light fixtures to enable use of these same fixtures for T-5 fluorescent lamps.
These T-8 light fixtures, however, were originally and optimally designed for use with T-8 imperial fluorescent lamps only. The various lengths of the T-5 fluorescent lamp are considerably shorter than the lengths of the standard T-8 lamp sizes as noted above. Thus, the existing T-8 lamp mounting hardware of conventional fluorescent fixtures is not practical for mounting of T-5 lamps when considering only the respective lengths of the lamp.
Concerning the electrical adaptability, existing T-8 lamp fixtures can be retrofitted to be more energy efficient, enabling T-5 lamps to be placed in these fixtures. Since fluorescent light fixtures designed for use with T-8 lamps are optimized in view of the characteristics of the T-8 lamp, a retrofit must necessarily provide the best possible photometric performance for T-5 lamps in light of that which is conventionally provided for T-8 lamps. In addition, there is a need for a retrofit that accommodates differing lengths of the T-5 or similar lamps. This retrofit must have a minimum number of physical parts devoted to this purpose. These parts must be inventoried in advance of actual assembly to conventional T-8 fixtures.
Thus, a need exists for an adapter for fluorescent lamp fixtures that retrofit a T-8 lamp fixture for a T-5 fluorescent lamp that is simple and inexpensive.
The present invention is directed to overcoming, or at least reducing the effects of one or more of the problems set forth above.